The father-to-be declared he’s gone from being a ‘deluded c***’, who did naughty things in club loos, to penning happy love songs.

On the imminent arrival of his and wife Ayda Field’s baby, he said: ‘I was calm at the beginning, then I gave up smoking and, I don’t know if it was because of the nicotine leaving my system, but I started to worry.

‘I always considered myself to be perpetually 18 and now I can’t be.

‘Also, you go through therapy and blame your parents – now all of a sudden you’re a parent and there’s no one to blame any more. Your child could blame you.’

Worried about being a good role model, he continued: ‘I’ve been famous since I was 16. I’ve never had to do anything for myself. Hopefully that will continue.

‘But what if it didn’t and I have to bend and form another person? There are all these concerns.

‘And then I just chilled out as we had an interview with a nanny. They’re like the oracle of little baby people.’

Reflecting on his wild past, the 38-year-old insisted he never made a sex tape but admitted: ‘I think I was videoed once but it didn’t work. It had been set up. I was obviously glad that it didn’t work because it involved copious amounts of cocaine.

‘Right now, being married for so long, if I could go back in time I’d have done a couple of sex tapes, I think.’

As for Mrs Williams, 33, he says she’s the one.

‘You know there’s so much positive stuff going with the two of us; she’s really kind and attentive and wants the best for people and wants to help them,’ the cocky singer told GQ magazine.

Robbie Williams on the cover of October’s Men of the Year issue of GQ

‘Once I’d seen that in her, it made me feel good that she wanted to be with me, which must mean that I’m actually good, so I was like, well, let’s cultivate this.

‘I went all the way through my twenties thinking I was sentenced to a life of mental imprisonment but I’m in a better place now.’

Recalling his former self, he added: ‘I was absolutely f***ing deluded.

‘Gigs really aren’t my thing… I was more interested in being in the toilets.’

Williams said there will be no misery or wallowing on his forthcoming solo album, Take The Crown.

He said: ‘Most of my songs are usually about feeling rubbish. I’ve managed to write a happy album.

‘Normally it’s a scramble to just get a single. Now I’ve got the option of about eight.’

Read the full interview in the October Men of the Year issue of GQ, on sale now.